Abstract
Real terrain is complex and its effects on the atmosphere are not well understood. The two‐dimensional change‐of‐roughness problem is investigated in an experimental study of airflow from mustard to fallow. The surface friction velocity is found to overshoot and return slowly to the equilibrium value. The wind profile in the modified region is more nearly logarithmic than the Peterson model predicts. The simple Elliot theory is in fair agreement with the wind profile data.
Values for the ratio of the standard deviation of the vertical wind to the friction velocity reveal no variation with stability and are in close agreement with the value for laboratory flows. Values for the ratio of the standard deviation of the longitudinal wind component to the friction velocity are comparable to other recently determined atmospheric values and show a variation attributable to large‐scale terrain properties.